Why are some substances biodegradable and some non-biodegradable? 

This article will explain why some materials are biodegradable and why some materials are not. Other topics covered would include: 

  • What determines biodegradability?
  • What are examples of biodegradable and non-biodegradable materials?
  • How much time is required for biodegradable and non-biodegradable materials?
  • If something is biodegradable, can it be composted too?
  • What is the relation between biodegradability and recycling?
  • Can biodegradability be fostered?
  • FAQs

Why are some substances biodegradable and some non-biodegradable?

The main reason why some materials are biodegradable and some are not is the extent of naturality of their constituents. When something is made from natural materials, it is more likely to be degraded by microbes as microbes can use it as a source of food. 

A product is regarded as biodegradable if it degrades in about 180 days. If not, then it would not be included in the list of biodegradable materials. 

Biodegradable materials usually can be composted but there may be certain exceptions as well. For example, Drywall mud is a biodegradable material but it also releases gases such as hydrogen sulphide when it degrades. That is why it can not be composted because it will do more harm than good.

What determines biodegradability?

In order to understand that, let us first introduce ourselves to the definition and explanation of biodegradability. 

Biodegradability is the degradation that is brought by the action of microbes and the facilitation of external factors such as sunlight, heat, temperature, and pressure. 

The microbes that cause biodegradation include bacteria, fungi, algae, protozoa, yeast, and decomposers. These are the hidden workers that cause the fruits and meat to rot. 

Biodegradability is an important parameter to assess how eco-friendly a product or material is. If something is biodegradable, chances are that it will be eco-friendly too because it will not contribute towards the waste problem and accumulation. 

There is a general rule of thumb about biodegradability natural materials are more prone to biodegradation as compared to non-natural materials. But, why is that? Let us ask the important question: what determines biodegradability?

The primary reason that determines if something is biodegradable or not is the inherent biology of that substance. If the substance or material is made from something that can be used by the microbes as food then that product will be biodegradable. 

If something or some product is made from materials that can not be used by the microbes as food then it will not be biodegradable. 

In some ways, biodegradation can be made equivalent to a form of symbiosis which is called mutualism. In mutualism, both organisms get benefitted. The benefit that microbes get is that they feast on the product as food. 

What are some examples of biodegradable and non-biodegradable substances? (7 examples of biodegradable materials)

Let us explore some examples to further our understanding of the concept of biodegradation. Consider the following examples of biodegradable materials: 

  • Food waste
  • Manure
  • Sewage waste
  • Plant waste
  • Animal waste
  • Animal skin
  • Waste from slaughterhouse

As expressed, natural materials are more likely to be biodegradable because these materials are made from biomolecules which can be used as food by the microbes. 

Now, let us explore some examples of non-biodegradable materials: 

  • PVC
  • PET 
  • Rayon fabrics
  • Electronic waste
  • Hazardous waste
  • Nuclear waste
  • Chemical waste

As can be seen, non-biodegradable materials are mostly resulting from synthetic chemicals and derivatives of fossil fuels. As a result, these substances are considered hazardous and harmful to the environment as they contribute towards environmental anomalies such as: 

  • Global warming
  • Greenhouse effect
  • Rising sea levels
  • Unprecedented weather patterns
  • Deforestation
  • Ozone depletion
  • Acid rains

How much time is required for biodegradable and non-biodegradable substances?

The time taken by substances is one of the important parameters to assess if something is biodegradable or not. As a general rule of thumb, a product is considered biodegradable if it degrades by the action of microbes in about 180 days in natural conditions. 

If a product or material takes more than 180 days, it will not be considered biodegradable. For example, natural fabrics may degrade in about 1-6 months. However, when it comes to non-natural materials such as plastics, the duration may diverge to more than a thousand years. 

The more time taken by a material to degrade, the greater pressure it will create on the waste management systems. The waste scenario is already quite dense since the waste generation is at a staggering figure of more than 2 billion tons. 

Biodegradation is a very important ally in this battle against waste accumulation. The more biodegradable waste produced will mean that the easier it will be to win this battle against waste accumulation. 

If something is biodegradable, can it be composted too?

Composting is the process of making compost from waste. This compost can be used as a natural fertiliser that can replace synthetic fertilisers. 

Composting is a green alternative because it offers a number of benefits that include: 

  • Increased soil fertility 
  • Increased water retention profile
  • The increased organic content of the soil
  • Better yield
  • Decreased use of agrochemicals

As a general rule of thumb, yes it is very likely that if something is biodegradable, it can also be composted. Like biodegradation, composting is yet another important ally in the battle against environmental degradation. 

This is because the compost can be used as a natural fertiliser which has a number of benefits. Natural fertilisers can replace synthetic fertilisers which can save us from soil and groundwater pollution and contamination. 

Compost can also improve the water retention ability of the soil. This implies the conservation of groundwater. The water saved from here can be utilised in many opportunistic ways since water is already a very limited resource and needs to be treated accordingly. 

Compost can also be used to improve the fertility of the soil and the yield of the crops. This not only indicates substantial benefits but also refers to economic benefits and perks. Hence, the pros of composting are not only limited to the environment but also diverge to the economy too. 

However, there are certain exceptions too. For composting, there are certain requirements such as: 

  • The product or material must be non-toxic
  • The material should not emit harmful fumes
  • The material should not have degradative side effects
  • The material should have a decent amount of organic content

Let us take the example of drywall mud. Drywall mud is a biodegradable material but it also releases gases such as hydrogen sulphide when it degrades. That is why it can not be composted because it will do more harm than good. 

What is the relationship between recycling and biodegradation?

Recycling can be explained as the reusing of cardboard boxes after processing and modifications. 

Recycling offers the following advantages: 

  • Better waste management
  • Better resource management
  • Decreased pressure on raw materials
  • Decreased carbon footprint
  • Decreased energy consumption

When materials are recycled, they are not required to be made from scratch. This saves energy and pressure on raw materials. Let us say something is made from trees. When it is recycled, fewer trees will be cut. 

This is important because we already face grave scenarios in the context of tree cutting. It is estimated that since the conception of human ways, the tree count has decreased by more than 50%. 

Trees are the essential entities that save us from environmental anomalies. Trees are regarded as the environment cleaner because they suck carbon dioxide and release oxygen. 

Carbon dioxide is a greenhouse gas that is responsible for the causation of environmental anomalies such as global warming, deforestation, acid rain, and weather changes.

As per the relation, there is no blunt or specific relation because both biodegradable and non-biodegradable materials can be recycled. 

Can biodegradability be fostered?

Let us now heed a very important question which is whether can biodegradability is fostered or not. What this means is can something be made biodegradable if it were not biodegradable in the first place?

Yes, it is possible and there are many examples of that. The main factor that discerns if something is biodegradable or not is the extent of naturality in its constituents. 

Let us take the example of plastics. Plastics are synthetic polymers that are mostly made from the derivatives of fossil fuels. That is why plastics are regarded as being non-biodegradable. 

In some studies, it is even claimed that some plastics may even require more than a thousand years to degrade which basically is a ‘never’. However, with technological advancements, a new form of plastic is made which is called bioplastics. 

These plastics are made from natural sources that include sugar cane, sugar beets, mushrooms, cornstarch et cetera. That is why these plastics are considered biodegradable. However, the biodegradation time of these plastics is not that impressive but at least, we are on the way. 

Other than that, there are countless studies that have been incessantly done that induce biodegradation of a substance that originally was not biodegradable. 

Therefore, it can be concluded that biodegradation can be induced with the help of science and a green proclivity. 

Conclusion

It is concluded that the main reason why some materials are biodegradable and some are not is the extent of the naturality of their constituents. When something is made from natural materials, it is more likely to be degraded by microbes as microbes can use it as a source of food. 

A product is regarded as biodegradable if it degrades in about 180 days. If not, then it would not be included in the list of biodegradable materials. 

Biodegradable materials usually can be composted but there may be certain exceptions as well. For example, Drywall mud is a biodegradable material but it also releases gases such as hydrogen sulphide when it degrades. That is why it can not be composted because it will do more harm than good. 

Frequently Asked Questions: Why are some substances biodegradable and some non-biodegradable?

What is the difference between degradation and biodegradation?

Degradation is the breakdown caused by chemicals but biodegradation is the breakdown caused by microbes or enzymes. 

If something is biodegradable, is it eco-friendly too?

Yes, it is generally perceived that biodegradable material is eco-friendly too. However, there can be exceptions too. 

References

Tokiwa, Y., Calabia, B. P., Ugwu, C. U., & Aiba, S. (2009). Biodegradability of plastics. International journal of molecular sciences, 10(9), 3722-3742.

Pagga, U. (1997). Testing biodegradability with standardised methods. Chemosphere, 35(12), 2953-2972.

Angelidaki, I., & Sanders, W. (2004). Assessment of the anaerobic biodegradability of macropollutants. Re/Views in Environmental Science & Bio/Technology, 3(2), 117-129.

de Bertoldi, M. D., Vallini, G. E., & Pera, A. (1983). The biology of composting: a review. Waste Management & Research, 1(2), 157-176.

Kale, G., Kijchavengkul, T., Auras, R., Rubino, M., Selke, S. E., & Singh, S. P. (2007). Compostability of bioplastic packaging materials: an overview. Macromolecular bioscience, 7(3), 255-277.

Matjašič, T., Simčič, T., Medvešček, N., Bajt, O., Dreo, T., & Mori, N. (2021). Critical evaluation of biodegradation studies on synthetic plastics through a systematic literature review. Science of the Total Environment, 752, 141959.

What was missing from this post which could have made it better?

Leave a Comment